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Check your user is human. Have him retype a word in a graphic
Do you have trouble with automated programs completing forms on your websites and making cart loads of submissions? Or even just a few spammers submitting their betting ads, performance enhancing pill sites, and share purchase suggestions? And yet you don't want to have to have anyone who wants to use your site register. Using what has become known as captcha technology, you can display a graphic with some text on what's basically a login page, then have your human user type that text back in. It's very difficult indeed for automata to recognise the text, and can be doubly so if you vary the background, change fonts between characters and change text colour, scale, rotation. Mind you, you can make it pretty tough for the human too. You'll find captcha in use already on many big sites, and there are other sites that will host the service for you. Actually, if you've got PHP available and the GD module it's very easy to code it up from first principles and that gives you the ultimate of flexibility. * Try my demo here * Show source code of main demo * Show source code of graphic generator (written 2006-07-17, updated 2009-01-14) Associated topics are indexed under A192 - Web Application Deployment - Firewalls[3680] How can I run multiple web servers behind a single IP address? - (2012-04-02) [3679] Setting up your Linux system as a firewall using iptables - (2012-04-02) [770] Splash! - (2006-06-20) G903 - Well House Consultants - Running and moderating forums [4065] Handling requests to a forum - the background process - (2013-04-17) [4025] Backups, Codebase, Strategy and more - dealing with forum incidents - (2013-03-03) [4017] Acceptable User Policy / vexatious interacter - (2013-02-24) [3910] Identifying your real customers and keeping them well informed fast - (2012-11-02) [3479] Practical Extraction and Reporting - using Python and Extreme Programming - (2011-10-14) [2820] Netiquette for forum newcomers - (2010-06-20) [2781] The 500 pound question to get you started - (2010-05-26) [2569] How to run a successful online poll / petition / survey / consultation - (2010-01-10) [2527] Flying tonight - (2009-12-05) [2526] A reluctance to move from old shoes to new - (2009-12-05) [2386] Computing under the influence of alcohol - (2009-08-29) [2254] Forum membership - a privilege not a right - (2009-06-22) [2177] Preventing forum spam - checks at sign up - (2009-05-12) [2162] Admins thoughts on banning a member from a forum - (2009-05-09) [2156] Stopping forum spam - control of the signup process - (2009-05-04) [2116] Why do we delay new forum members through authorisation? - (2009-04-03) [2103] Ask the Tutor - Open Source forum - (2009-03-25) [1972] Pettifog and forum boards away from public view - (2009-01-03) [1923] Making it all worthwhile - (2008-12-04) [1759] While the world sleeps ... - (2008-08-19) [1678] Software - changes and delays. 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Link to page ... 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82 at 50 posts per pageThis is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.
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